The present invention relates to a method and an apparatus for aligning an optical device such as a collimator.
FIG. 13 is a schematic diagram illustrating a conventional fiber collimator aligner. The fiber collimator aligner optimizes a fixed position of an optical fiber 36 with respect to a capillary 35 to align a collimator 32. More specifically, in the conventional aligner, light emitted from a light source 51 reaches a mirror 14 through a first branch optical fiber 52 and an optical splitter 53. The light 59 reflected by the mirror 14 is converged by a collimation lens 34 and impinges on a light intensity measuring device 75 through an optical fiber 36, an optical splitter 53 and a second branch optical fiber 54. The light intensity measuring device 75 measures the intensity of the reflected light 59. A pedestal 111 rotatably supports the mirror 14 about an X-axis or a Y-axis to change the angle of the mirror 14 to the optical axis.
A conventional aligning method is performed in the following manner. First, the mirror 14 is rotated about the X-axis such that the light intensity detected by the light intensity measuring device 75 reaches a maximum to adjust the angle of the mirror 14. Next, the position of the optical fiber 36 with respect to the collimation lens 34 is changed along the Z-axis such that the light intensity measured by the light intensity measuring device 75 reaches the maximum. The mirror 14 is again rotated about the Y-axis such that the light intensity detected by the light intensity measuring device 75 reaches the maximum. After adjusting the angle of the mirror 14, the position of the optical fiber 36 in the Z-axis direction is changed such that the light intensity measured by the light intensity measuring device 75 reaches the maximum. After locating an optimized position by repetitions of the forgoing operations, the optical fiber 36 is fixed to the capillary 35 at that position.
In the foregoing manner, the conventional aligning method and the aligner independently swing the mirror 14 in the vertical direction and in the horizontal direction. In other words, the pedestal 111 changes the angle of the mirror 14 with respect to the optical axis separately about the X-axis and Y-axis. Therefore, the aligning operation involves a trial and error process in which the mirror 14 is rotated about one axis such that a measured value of the light intensity measuring device 75 reaches the maximum, followed by an adjustment of the position of the optical fiber 36 in the Z-axis direction. As a result, the aligning operation takes a long time.